There is increasing evidence from both epidemiologic and laboratory studies for an association between sleep duration and/or quality and the prevalence and/or severity of major chronic diseases, including diabetes and cardiovascular disease. Sleep disturbances, particularly sleep disordered breathing (SDB) and periodic leg movements (PLM), are more prevalent in patients with chronic kidney disease (CKD) than in the general population. Because the hormones involved in the control of kidney function are markedly modulated by sleep, it is possible that sleep disturbances have an adverse effect on kidney function. The present proposal therefore seeks to explore the role of decreased sleep duration and/or quality as a risk factor for the progression of chronic renal insufficiency and the development of cardiovascular disease in CKD. This study has two over-arching hypotheses: 1. Sleep quality will be a predictor of the progression of CKD, and 2. Sleep quality will be a predictor of cardiovascular disease in CKD. This project will be an ancillary study to an ongoing longitudinal cohort study, the Chronic Renal Insufficiency Study (CRIC). Specific Aim 1 will involve assessment of habitual at-home sleep duration and quality (by wrist and leg activity monitoring, logs and questionnaires) to predict changes in renal and cardiovascular measures over study period in CRIC subjects. Specific Aim 2 will examine changes in polysomnographic variables, including measures of SDB and PLM, to predict changes in renal and cardiovascular measures over study period in CRIC subjects. Specific Aim 3 will delineate the relationship between hormones controlling body fluid balance, cardiovascular function and sleep in mild to moderate CKD patients as compared to normal controls to identify possible pathophysiological mechanisms. Overall, the proposed studies will determine if poor sleep quality accelerates the development or increases the severity of CKD and of cardiovascular disease in CKD and if strategies to improve sleep quality may have beneficial effects on CKD.